Hi Bud, welcome to the Board. My view on this is that these are all MLB players who took a very long road of success and failure at many levels of ball to get to where they are.
A hitting coach can help identify or tweak issues and approach, but they have no authority to direct an approach or swing. Nor should they. So their incremental influence is actually fairly minimal. MLB players have so much info and know themselves and their swings well. Its what puts food on their families tables.
Its actually a matter of preference. If you polled the players in confidence a certain percentage would like Martinez, and others would prefer another they had in the past, or whatever. Sometimes they click, sometimes they don't. It really doesn't make that much difference at the MLB level.
The team has much bigger challenges to deal with.